Studies involving human subjects are integral to adult and pediatric oncology, and the field therefore demands careful attention to research ethics. At the same time, cancer clinical investigation can be viewed as a laboratory in which to test conceptual claims in research ethics. The studies described in this application address key challenges in the ethics of cancer-related research. Project 1 will review all randomized clinical trials (RCTs) conducted by 3 national cancer cooperative groups over the past 2 decades. Its major goal is to describe the proportions of RCTs that found the control arm to be superior, the experimental arm to be superior, or the 2 arms to be equivalent. These proportions will form the basis of a judgment about whether equipoise as a systematic feature of cancer RCTs exists. Project 2 is a conceptual project to consider whether it is possible to justify enrolling subjects late in an RCT, when preliminary data may point strongly but not conclusively to the superiority of one arm or the other. We will examine the key ethical assumptions underlying the choice of stopping rules for RCTs, and then challenge those assumptions from both the empirical and conceptual points of view. Finally, in Project 3 we will survey a large number of cancer patients about their attitudes towards prospective Consent to use of tissue samples in future research studies. This is a controversial area of ethics and policy, and the outcome of the current debate is likely to have considerable repercussions for cancer research. Our findings will inform policy by ensuring that the wishes and priorities of cancer patients are heard. With the mentorship of Drs. Ezekiel Emanuel, Jane Weeks and Robert Truog, this award will permit Dr. Joffe to gain the skills and experience necessary to be a successful independent investigator at the dynamic intersection of clinical, empirical and conceptual research ethics. In addition to supporting the research described here and coursework at the Harvard School of Public Health and Kennedy School of Government, this award will foster Dr. Joffe's development as a local and national resource in research ethics for the oncology community.